"Japanese Grammar 100" is not a comprehensive textbook; nor is it intended to be one. But once you have learned the Japanese "alphabet" (Hiragana and Katakana) and some basic vocabulary, this book can serve as an excellent introduction to sentence structure, verb forms, possessives, question words, pronouns, etc. Each lesson is brief, clear, and easy to understand. The book also provides references to online practice for the beginner - very useful.
Having worked as a language teacher for years, I know that a lot of students just hate grammar. (Of course I love it! ;-) Since I started to try to learn Japanese I have been looking for some simple way to get a grip of the system of the Japanese grammar, and here it is!!
I am sure there is a lot more to learn, but for me this was a great introduction.
So: Forget your fears and hate, and give this a try!